# CLI Builder — Design Agent-Friendly CLI Tools

A comprehensive design guide and scaffold for building CLI tools that **AI agents can actually use**. 10 universal design patterns grounded in real failures from building 15+ agent-facing CLIs.

## Why Install This Skill

When your agent loads this skill, it can **design, build, and refactor CLI tools** that agents can discover and use without human help. The goal is to establish and review explicit contracts for help, output, safety, and repeatable operations:

- **Treat `--help` as a contract** the agent parses to understand your tool
- **Establish a documented `--json` contract** for machine-readable output, when the CLI supports it
- **Design and verify idempotent operations** where repeatability is appropriate, with `--dry-run` previews for changes
- **Authentication is lazy** — help and dry-run work without credentials
- **Errors are structured** — different exit codes for different failure modes

## What You Get

| Directory | Purpose |
|-----------|---------|
| `SKILL.md` | Concise workflow for discovery, predictable contracts, verification, and maintenance |
| `templates/` | Bash CLI scaffold for local wrappers |
| `references/` | Python API clients, advanced patterns, readiness checklist, wrapper example, MCP decisions, and improvement cycle |

## Triggers

Load this when building a new CLI tool, refactoring an existing tool that causes agent friction, or debugging why your agent keeps failing to use a CLI properly.

## Requirements

Bash, Python 3.8+, jq, and a standard Unix CLI environment.


## Quick Start

Start with the setup and first workflow in SKILL.md, then use the linked resources for the specific task you need to complete.